Dechanneling by dislocations in ion-implanted Al
The first comprehensive ion-backscattering study of the influence of dislocations on the dechanneling of energetic channeled ions has been carried out. High dislocation densities were obtained in the near-surface region of single-crystal Al by implantation of 6.6 x 10/sup 16/ Al/cm/sup 2/ or 2.6 x 10/sup 16/ Zn/cm/sup 2/. Independent analysis of the disorder introduced by the Al and Zn implantations, as well as a quantitative measure of the total length of dislocation lines per cm/sup 2/, were obtained by transmission-electron microscopy. Dechanneling measurements were made by means of ion backscattering for H/sup +/ and He/sup +/ ions ranging in energy from 0.5 to 2.8 MeV, incident along the <110> axial and )111) planar channeling directions. For these experimental parameters a systematic dependence of the dechanneling versus depth is demonstrated. These experimental observations are characteristic of that predicted theoretically for dechanneling by dislocations and distinctly different from that observed for randomly displaced atoms. The theoretical analysis for the data reduction is developed to obtain the dechanneling cross section for dislocations from the experimental data for both axial and planar channeling. The results are in agreement with independent theoretical calculations of the dislocation dechanneling cross section by Quere, both quantitatively and in the functional dependences of the dechanneling parameter on energy, ion type, and channeling direction. From these studies the measurement of dislocation density by single alignment channeling is estimated to require 10/sup 9/--10/sup 10/ dislocation lines per cm/sup 2/. Although axial channeling has been used in the past for depth profiling measurements of disorder by backscattering, the large dechanneling cross sections and well-defined dechanneling behavior shown here for planar channeling suggest that planar analysis may be more suitable than axial for determining the depth distribution of dislocations by channeling-effect measurements.
- Research Organization:
- Sandia Laboratories, Albuquerque, New Mexico 87185
- OSTI ID:
- 6645908
- Journal Information:
- Phys. Rev., B; (United States), Journal Name: Phys. Rev., B; (United States) Vol. 18:5; ISSN PLRBA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360104* -- Metals & Alloys-- Physical Properties
ALUMINIUM
BACKSCATTERING
CATIONS
CHANNELING
CHARGED PARTICLES
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DISLOCATIONS
ELEMENTS
HELIUM IONS
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
ION CHANNELING
ION IMPLANTATION
IONS
LINE DEFECTS
METALS
SCATTERING